The chaperoning definitely didn’t help matters.
Indeed, making your move earlier may have led to a different result but it really isn’t beneficial to dwell on that.
You weren’t too harsh.
Yes, you did stand up for yourself and that was what you had to do.
You know what you want.
There is no point in putting out the effort to court someone while bearing the inconveniences of having a chaperone tag along, if the person in question doesn’t share the same romantic interest.
You aren’t looking for friendship after all.
You have left the door open to her, if she were to change her mind.
As of now, your task is to move forward.